Thermal responsive actuator



March 12, 1963 w. E. BAKER 3,080,756

THERMAL RESPONSIVE ACTUATOR Filed Dec. 5, 1958 INVENTOR WILLIAM E. BAKERHIS ATTORNEYS n e S s Patent I1 3,080,756 THERMAL RESPONSIV E ACTUATORWilliam E. Baker, Needham Mass, assignorto Standard- ThomsonCorporation, Waltham, Mass., a corporation of Delaware Filed Dec. 5,1958, Ser. No. 778,520

9 Claims. (Cl. 73-3683) This invention relates to a thermal responsiveactuator; This invention isan improvement upon'the thermal responsiveactuator of Patent No. 2,806,375, assigned to Another object of thisinvention is to provide such asealing." 'means' which is capable ofeffective sealing throughout a'very high number of operations of theactuator rod.

Another object of-this invention is to provide 'a thermal responsiveactuator which maybe produced at-compar'a tively low cost.

"Other objects and advantages reside in the construction of parts,'the'combination thereof, the method of manufacture, and the 'mode ofoperation, as will become more apparent from the following description.

'-In.the drawing,- FIGURE'I is a sectional view of a thermal responsiveactuator of this invention, showin the actuator in a deactuatedcondition.

FIGURE 2 is a sectional view similar to FIGURE l,

showing the actuator. in an actuated position.

FIGURE 3 is a sectional view taken-substantially online 3--3- ofFIGURE 1. I v

"FIGURE 4- is a fragmentary sectional view showing a portion of asealing means fora reciprocally operable actuator rod with the actuatorrod removed. Referring-to the drawing in detail, a thermalresponsive-actuator of this invention'comprises a container which may besubstantially cylindrical-in shape. The

container 10 has a diverging end portion 12 within which acover member14 is disposed- The cover member 14 is held firmly against the divergingend portion 12 by means-of a bent-over portion 16, as clearly shown inFIGURES 1 and 2.

"Ihe cover member '14 is provided with-an opening therethrough atsubstantially the center thereof. The edge of the opening on the innersurface of the cover member 14 is arcuate, as shown by reference numeral20.

face of the'cover member 14 and integral therewith is a hollow ne'clt'22having an arcuate bent-over end 24. A

body of elastic material or elastomeric material 25 has a main portion26 within the container 10. The main portion 26 has a-flange 28 whichengages the cover mem ber 14 and the diverging portion 12 of thecontainer 10.

22 and the bent-over portion 24 thereof. Preferably the flangeZS-and-the portions 30 and 32 of the elastic body 25 are bonded to thecover member- 14 by any suitable means.

lheelastic body 25 has abore or cavity 34 therein, as

high fluid pressures within the shown in FIGURE 4. The bore or cavity 34extends through the portions 32 and and into the main portion" 26. Wallmembers 36 form the portion of the bore'34 which is withi'n'the mainportion 26, as shown in FIG URES l, 2, and 3. The cavity 34 extendsthrough most of the length of the main portion 26 of the elastic'body-25. i

The bore 34 is adapted to snugly receive an actuator rod 40 which isshown as being provided with .a tapered end 42-, as shown in FIGURES land 2.

Within the container 10 and exterior of the elastic body I 251s a bodyor quantity of thermal responsive expansible contractible' material '44.The thermal responsive mate rial 44 may preferably be any material suchas wax orl the like. This thermal responsive expansive material 44 maybe any element or any combination of elements giv- 1 mg the material thephysical property characteristics of i a high coetficient of expansionover a given temperature range. A material is selected to provide thedesired ex pansion and flow characteristics over the desired temperaturerange for any given application of the thermal. responsive device.

- As shown in FIGURE 4, the upper end of the portion I 32 of the elasticbody 25 has an opening forming the mouth of the bore 34. The diameter ofthe opening 50" is'slightIy smaller than the'diameter of the actuatorrod! 40. The wall surface of the'bore 34,adjacent the open-I; ing 50 isprovided with a series of tapered annular'por-i tions- 51. Each taperedportion 51 of the wall surface of the bore 34 terminates in a diameterlarger than the opening 50. Also, the wall surface of the bore 34 withinthe portion 32 of the elastic body 25 has a pluralityof surfaces 52which are substantially normal to the axis" of the bore 34. Each of thesurfaces 52 has an opening' therein substantially equal to the opening50. Therefore,

when the actuator rod 40 is disposed within the bore 34,

- the portion 32 firmly seals against flow of fluids into the :55Extending substantially normally fromtheouter suit bore or cavity 34.Thus, fluids are prevented from flowing along the surface of the rod 40into the cavity or bore34. FIGURE 1 shows-a thermal responsive actuatorof this' invention in a deactuated condition. However, upon subjectionof the actuator to additional heat the thermalresponsive expansivematerial 44 expands. As best shownin FIGURE 3, the area'of the enclosingwalls 36 is greater than the area of the cavity or bore within whichthe'rod- 40 is snugly slidably disposed. 'It has been found that whenthis ratio exists, i.e., in which the cross sectional area of theenclosing walls is equal to or greater than'ther area of the cavitywithinth'e elastic body, a squeezing or extrusion action occurs duringexpansion of the material" 44, as shown'in FIGURE Z. 1 1 Therefore, theactuator rod 40 is squeezed from the cavity orbore 34, as'the'walls 36move inwardly, as shown in FIGURE-2. This extrusion action or squeezingaction is distinguished from'diaphragm action in that in dia-- phragmaction the sealing-member follows the 'end offanactuator rod so that thebottom end of the sealing member remains or tends to remain inengagement with the endof the actuator rod as the actuator rod is forcedin a direction from the container. During such diaphragm action stressesupon the sealing material are high.

Due to the fact that the actuator rod of this inven-' tion is squeezedor extrudedfrom within the bore 34 of the elastic'body 25, as shown inFIGURE 2, the walls; 36 move smoothly inwardly during expansion of themate-'- rial 4-4." Thus, there are only small stresses'upon the walls I25 bonded thereto, aidsinguiding the movement of the Patented Mar. 1 2,1963 a 3 actuator rod 40 as the actuator rod 40 moves through theopening in the cover member 14. Of course, the pressures Within thecontainer are very high during the extrusion action which is illustratedby FIGURE 2, these pressures being caused by expansion of the material44. Therefore, forces upon the elastic material adjacent the openingthrough the cover member 14 are very high. Due to the fact that theedges of the inner and outer surfaces of the cover member 14 arearcuate, as shown by referencenumerals and 24, and due to the fact thatthe elastic body has a portion extending through the opening and alongthe neck 22, the per unit forces and stresses upon the elastic materialadjacent the cover member 14 are reduced. The stresses upon the elasticmaterial adjacent the opening through the cover member 14 aresufiiciently low so that there is little possibility of failure of theelastic material adjacent the opening through the cover member 14. Thus,the neck 22 with the elastic material adjacent thereto serves as anexcellent guide and sealing means for movement of the actuator rod 40through the opening in the cover member 14.

From the above discussion and the drawing it is to be understood thatthe thermal responsive actuator of this invention is capable of longlife and has accuracy, dependability and consistency.

Although the preferred embodimentof the devicehas been described, itwill be understood that within the purview of this invention variouschanges may be made in the form, details, proportion and arrangement ofparts, the combination thereof and mode of operation, which generallystated consist in a device capable of carrying out the objects setforth, as disclosed and defined in the appended claims.

-Having thus described my invention, I claim:

1. In a thermal responsive actuator, a container provided with tanenclosing wall having an aperture therethrough, the aperture having anarcuate edge on the inside surface of the wall, a hollow neck attachedto the outer surface of the wall and encompassing the apers ture, theneck having an inner surface and an outer sur-- face, a body of elasticmaterial disposed withinthe container and extending from the containerthrough the aperture in said wall, the body of elastic material beingbonded'to the wall on the inside and outside thereof, the elasticmaterial also being disposed on the inner and outer surfaces of the neckand bonded thereto, the body of elastic material having a wall memberforming, a bore therein; the thickness of the-wa1l member within theneck being much less than the thickness of the wall member withinthecontainer, the bore being in the. portionsof the body of elasticmaterial within the-neck and on both sidesof thewall, an actuator rodwithin the bore and reciprocally movable with respect to the wall, and abody ,ofthermal responsive work producing material within the containerand exterior of the body of elastic material.

. body of'elastomeric material also-being bonded to said neck, thebodyof'elastomeric material having a wall form- 'ing a bore therein'whichextends through saidopening and through said neck, thethickness of thewall of the V portion ofthe bore'within the neck being muchiless thanthe" thickness of the wall forming the remainder of the bore; and areciprocally movable rod member disposed withinsaid bore. j e e g r 3;.In a thermal responsive ac u or, avcon'tainer, the container having awall provided with an opening therethrough, the wall having an innersurface and an outer 1 surface, the edge of the opening being ,arcuateat the 2,, In a thermal responsive actuator,-,a container pro r innerand outer surfaces of the wall, a body of elastic material bonded to thesaid wall, a main portion of the body of elastic material being withinthe container, an intermediate portion of said body of elastic materialex tending through said opening in 'the wall, an auxiliary portion ofthe body of elastic material being disposed on the outer sur'face of thewall and extending therefrom, the body of elastic material having wallmembers forming a bore therein which .extendsthrough the auxiliary andintermediate portions and intojthelma'in portion thereof, the thicknessof the wall members forming the bore of the intermediate portion beingmuch less than the thickness of the wall members forming the remainderof the bore, an actuator rod snugly disposed and reciprocally movablewithin the bore, and a body of thermal expansive material within thecontainer exterior of the body of elastic material.

, 4. In an actuator device, a wall member having an elongated circularpassage therethrough, a cylindrical 1 rod member extending throughthe'pa'ssage and recipro cally movable with respect to the'wall member,the di- 7 ameter of the rod member being considerably smaller than thediameter of the aperture so that a space exists between the rod memberand the wall member,,the pas sage in the'wall member having an inneredge and an outer edge, both of the edges being arcuate, a body ofelastomericnmaterial extending through the passage and encircling andengaging therod member and in engagement with opposite surfaces of thewall member, the thick ness dimension of the elastomeric material withinthe passage being considerably less than the thickness of the remainderof the body of elastomeric material. p

5. In a pressure responsive device, an enclosing wall having an openingtherethrough, the enclosing wall hav ing opposed surfaces, anelastomeric sealing member having portions thereof in engagement withboth surfaces of the enclosing wall, the sealing member also having anintermediate portion extending through the opening in the enclosingwall, the sealing member having an outer extending portion and an innerextending portion which extend from the enclosingjwali on opposite sidesthereof, the elastomeric sealing member having wall members forming acavity therein which extends through the intermediate portion andthrough the'outer extending :por-v tion of the elastomeric sealingmember, and through a part of the innerextending portion, the thicknessdimension of the wall members of, the cavity in the inter mediateportion being considerably less than the thick ness of the wall membersforming the remainder of the cavity.

6. Ina thermal'responsive actuator, an enclosingwall provided withanuaperture therethrough, a neck integral with ,the'wall and encirclingthe aperture, the neckextending'from' the wall on one side thereof,theneckhav ing an outwardlyextending flange at the end thereof, a bodyof elastic material extending through the aperture, the body of elasticmaterial also engagingthe wall and extending therefrom on opposite sidesthereonthe body of elastic material having a cavity therein, a portionof .the cavity being within the-neck,'ian actuator rod disposedwithinthe .cavity and reciprocally movable ,through the aperture in the wall,and thermal responsive means exterior ofai e' bodyof elasticmaterial.' j

.7. In ajthermal responsive actuator, a containerahav-, ing an enclosingwall, provided with an aperture therethrough, a neck exterior of thecontainenextending from the wall and integral therewith and-encompassingthe aperture, an elastic body having a main portion within thecontainer, the elastic body also, extending through the apertureand'through the neck and beyond the neck, the elastic body also having aportion onthe outer surface of the neck and onthe outer surface of theenclosing wall,

the elastic bodybeing bonded to the enclosing wall on both surfacesthereof, the elastic body having a bore therein extending through theneck and through the aperture and into the main portion of the elasticbody, and actu ator means Within the cavity.

8. In a thermal responsive actuator a container having a portionprovided with a neck forming an opening therethrough, the neck extendingfrom the exterior of the container, a body of elastomeric material inbonded engagement with opposite sides of the Wall and with oppositesides of the neck, the body having wall members forming a cavity thereinwhich extends through said neck, the cross sectional area of the portionof the wall members within the container being at least as great as thearea of the cavity but the cross sectional area of the wall memberswhich form the portion of the cavity extending through the neck beingvery small and much less than the area of the cavity.

9. In a pressure responsive actuator device, a rigid wall memberprovided with an aperture extending therethrough, the rigid Wall memberhaving an inner surface and an outer surface, both of said surfacesbeing arcuate at the edge of the aperture, elastomeric material bondedto both of said surfaces of the rigid wall member and extending throughthe aperture, the elastomeric material having resilient wall membersforming a bore therein, the bore extending through said aperture, thethickness dimention of the resilient wall members within the aperturebeing very small compared to the thickness dimension of the resilientwall members outside of the aperture, and a rod member slidably disposedwithin the bore.

References Cited in the file of this patent UNITED STATES PATENTS1,873,590 James Aug. 23, 1923 1,873,592 James Aug. 23, 1923 1,926,197Dun Sept. 12, 1933 2,507,466 De Craene May 9, 1950 2,517,717 Rose Aug.8, 1950 2,699,357 Roth Jan. 11, 1955 2,806,376 Wood Sept. 17, 19572,875,452 1959 Portolano Mar. 3,

1. IN A THERMAL RESPONSIVE ACTUATOR, A CONTAINER PROVIDED WITH ANENCLOSING WALL HAVING AN APERTURE THERETHROUGH, THE APERTURE HAVING ANARCUATE EDGE ON THE INSIDE SURFACE OF THE WALL, A HOLLOW NECK ATTACHEDTO THE OUTER SURFACE OF THE WALL AND ENCOMPASSING THE APERTURE, THE NECKHAVING AN INNER SURFACE AND AN OUTER SURFACE, A BODY OF ELASTIC MATERIALDISPOSED WITHIN THE CONTAINER AND EXTENDING FROM THE CONTAINER THROUGHTHE APERTURE IN SAID WALL, THE BODY OF ELASTIC MATERIAL BEING BONDED TOTHE WALL ON THE INSIDE AND OUTSIDE THEREOF, THE ELASTIC MATERIAL ALSOBEING DISPOSED ON THE INNER AND OUTER SURFACES OF THE NECK AND BONDEDTHERETO, THE BODY OF ELASTIC MATERIAL HAVING A WALL MEMBER FORMING ABORE THEREIN, THE THICKNESS OF THE WALL MEMBER WITHIN THE NECK BEINGMUCH LESS THAN THE THICKNESS OF THE WALL MEMBER WITHIN THE CONTAINER,THE BORE BEING IN THE PORTIONS OF THE BODY OF ELASTIC MATERIAL WITHINTHE NECK AND ON BOTH SIDES OF THE WALL, AN ACTUATOR ROD WITHIN THE BOREAND RECIPROCALLY MOVABLE WITH RESPECT TO THE WALL, AND A BODY OF THERMALRESPONSIVE WORK PRODUCING MATERIAL WITHIN THE CONTAINER AND EXTERIOR OFTHE BODY OF ELASTIC MATERIAL.